Are there any differences regarding say SPDs or AFDDs in Amd 1 or 2 that were not in the original?

Since amd2, SPDs are now always required if risk of injury/life, safety service or financial/data loss.  They are required elsewhere unless the owner formally declares that they're prepared to risk it. AFDDs for <= 32A sockets required for hi-rise, HMOs, student accommodation, care homes; recommended otherwise.

So from a landlord's perspective, AFDDs are likely to become a thing if and when the Landlord Regs are ever updated to include amd2.

Since amd2, SPDs are now always required if risk of injury/life, safety service or financial/data loss.  They are required elsewhere unless the owner formally declares that they're prepared to risk it. AFDDs for <= 32A sockets required for hi-rise, HMOs, student accommodation, care homes; recommended otherwise.

So from a landlord's perspective, AFDDs are likely to become a thing if and when the Landlord Regs are ever updated to include amd2.

So if you follow the law and only EICR to 18th Edition no Ammds you do not consider SPDs?

No, the landlords gets whatever I&T they want. If (and only if) that I&T happens to find a non-conformity with BS 7671:2018  first edition, then the landlord is supposed to rectify it. So if the inspector writes a report which (in part) says "you have no SPDs or AFDDs!!", the landlord is under no obligation to do anything about it. Of course, in practical terms a landlord might not realise this unless it's clearly spelled out in the report, and the tenants might make a fuss.